feat: register isphere file receive list tool

docs/current-status-card.md

@@ -14,7 +14,7 @@ Remote base before local roadmap commits: `b2d839e Merge branch 'codex/n15-repor
 ## Current completed state
 
 - Go MCP foundation exists: `cmd/isphere-mcp`, `internal/mcpserver`, `internal/helperclient`, and `internal/tools` build a stdio MCP server.
-- The current MCP surface exposes seven read-oriented tools:
+- The current MCP surface exposes eight read-oriented tools:
   - `win_helper_version`
   - `win_helper_self_check`
   - `win_helper_scan_windows`
@@ -22,14 +22,15 @@ Remote base before local roadmap commits: `b2d839e Merge branch 'codex/n15-repor
   - `isphere_receive_messages`
   - `isphere_search_contacts`
   - `isphere_search_groups`
+  - `isphere_receive_files`
 - C# `ISphereWinHelper` exists under `native/ISphereWinHelper` and uses the `isphere.helper.v1` stdin/stdout JSON contract.
-- `scripts/verify-win-helper.ps1` and `scripts/verify-go-mcp.ps1` provide repeatable local checks for the helper, seven-tool MCP surface, default empty-source receive/contact/group calls, and synthetic configured-source receive/contact/group smoke.
+- `scripts/verify-win-helper.ps1` and `scripts/verify-go-mcp.ps1` provide repeatable local checks for the helper, eight-tool MCP surface, default empty-source receive/contact/group/file calls, and synthetic configured-source receive/contact/group/file smoke.
 - N12-pre and N12R documents define safe offline evidence intake and internal-sandbox live UIA capture procedures.
 - N13/N14/N15 produced selector catalog/report validation infrastructure, but those are supporting validation assets only.
 
 ## What cannot be claimed externally
 
-- The project has not yet implemented business MCP tools for message sending, file receiving/download, or file sending; `isphere_receive_messages`, `isphere_search_contacts`, and `isphere_search_groups` have operator-local encrypted log-file support but not a production ingestion path.
+- The project has not yet implemented business MCP tools for message sending, file download, or file sending; `isphere_receive_messages`, `isphere_search_contacts`, `isphere_search_groups`, and `isphere_receive_files` list mode have operator-local encrypted log-file support but not a production ingestion path.
 - The project has not completed production iSphere integration.
 - The project has not proven a stable real message source for the full business workflow beyond decrypted PacketReader log evidence and synthetic/redacted tests.
 - The project has not implemented real message sending or real file upload.
@@ -41,8 +42,8 @@ Remote base before local roadmap commits: `b2d839e Merge branch 'codex/n15-repor
 - The repository has a Go MCP + C# WinHelper foundation for controlled Windows-side read-only observation.
 - The helper protocol boundary is explicit and keeps Windows/UIA work separate from the Go MCP service layer.
 - The current code can support future MCP business tools by routing low-level Windows/UIA fallback work through a bounded helper layer.
-- The project has repeatable verification scripts for the helper/MCP foundation and the current seven-tool surface.
-- The project now has a corrected business contract and plan for core MCP communication tools, plus registered receive/contact/group read tools that can use `ISPHERE_PACKET_LOG_FILE` for operator-local encrypted PacketReader log lines.
+- The project has repeatable verification scripts for the helper/MCP foundation and the current eight-tool surface.
+- The project now has a corrected business contract and plan for core MCP communication tools, plus registered receive/contact/group/file-list read tools that can use `ISPHERE_PACKET_LOG_FILE` for operator-local encrypted PacketReader log lines.
 
 ## N13/N14/N15 positioning
 
@@ -50,7 +51,7 @@ N13/N14/N15 are pre-business validation results. They can help identify UI eleme
 
 ## Current loop
 
-Current loop: `Stage C / Loop C14 - register isphere_receive_files list mode`.
+Current loop: `Stage C / Loop C15 - send message source evidence precheck`.
 
 Plan file: `docs/superpowers/plans/2026-07-09-stage-c-log-backed-receive-messages-loop.md`.
 
@@ -75,11 +76,12 @@ Current loop output so far:
 10. C10: log-backed group candidate extraction from groupchat/conference JIDs.
 11. C11: `isphere_search_groups` MCP registration and seven-tool verification.
 12. C12: file evidence precheck confirmed enough PacketReader/Smark evidence for file metadata listing, but not enough for real cache/download mapping.
-13. C13: `internal/isphere.ListFilesFromMessages` extracts synthetic/redacted file metadata candidates from normalized messages; MCP registration is next.
+13. C13: `internal/isphere.ListFilesFromMessages` extracts synthetic/redacted file metadata candidates from normalized messages.
+14. C14: `isphere_receive_files` MCP list mode registered and verify-go-mcp now covers eight tools plus default/configured file-list smoke.
 
 ## Next business mainline
 
-1. Run Stage C Loop C14: register `isphere_receive_files` list mode on top of `ListFilesFromMessages`.
-2. Leave actual download/cache mapping as a later connector node until a message-to-cache hash or client download source is validated.
-3. Add `isphere_send_message` and `isphere_send_file` after source discovery and connector selection.
+1. Run Stage C Loop C15: verify available evidence for `isphere_send_message` connector selection before implementing any write-capable path.
+2. Leave actual file download/cache mapping as a later connector node until a message-to-cache hash or client download source is validated.
+3. Add `isphere_send_message` and `isphere_send_file` only after source discovery, preview semantics, execution metadata, and audit shape are defined.
 4. Keep UIA selector/report work as fallback support, not as the primary roadmap.